Virial Description of Two-Component Adsorption on Homogeneous and Heterogeneous Surfaces

Abstract

The two-dimensional virial equation of state is used to describe the adsorbed phase on both homogeneous and heterogeneous surfaces. Heterogeneity is modeled by assuming that the adsorbent surface is composed of two patches. The adsorbed phase is assumed to be completely mobile, and the same virial coefficients represent adsorbate−adsorbate interactions on both patches. Experimental data for highly nonideal systems are accurately correlated using the two-patch model. A predictive approach is proposed for deducing the mixture coefficients from pure component parameters. The approach works reasonably well in predicting binary adsorption equilibria for simple systems.